Diagnostic Issues and Indications for Surgery in Patients With Pulmonary Artery Sling
To the Editor:
This letter is in reference to the brief article entitled “Combined Pulmonary Artery Angiography and Tracheobronchography in Pulmonary Artery Sling,” authored by Joachim Freihorst and Thomas Paul (Circulation. 1997;96:2079). The authors reported their evaluation of a 12-month-old child with inspiratory and expiratory stridor. Barium swallow showed an anterior impression of the esophagus (consistent with a pulmonary artery sling). Two-dimensional echocardiogram could not visualize the origin of the left pulmonary artery. The authors proceeded to do combined pulmonary angiography and tracheobronchography to diagnose the pulmonary artery sling. The figure showing the combined contrast injection in the pulmonary artery and lower trachea is a nice demonstration of pulmonary artery sling, but in my experience, these are 2 unnecessary studies. In our recent experience, the diagnosis of pulmonary artery sling has been possible in all cases with a comprehensive echocardiographic analysis.1 We reviewed 19 cases of pulmonary artery sling operated on over a 26-year period (1970–1996). Pulmonary arteriography demonstrated the pulmonary artery sling in 7 of 10 patients (70%). This procedure has not been performed at our institution since 1991. Two-dimensional color Doppler echocardiogram using suprasternal/high-parasternal sweeps diagnosed pulmonary artery slings in 7 of 7 patients (100%). Color Doppler demonstrated the site of take-off, course, and relative size of the left pulmonary artery as it arose from the right pulmonary artery. Tracheobronchography was not performed on the patients, but rather preoperative or intraoperative bronchoscopy was performed in all cases to rule out associated complete tracheal rings, which were present in 11 (58%) of the 19 patients. We concluded that in preparation for surgery, the diagnosis of pulmonary artery sling may be confidently made from echocardiography alone. Angiography is no longer indicated to diagnose pulmonary artery sling.
In addition, according to the article, this patient has not yet had surgical intervention, but “is doing well on physical therapy and close clinical follow-up.” Our recommendation has been that all children with respiratory symptoms and a pulmonary artery sling should have such malformations repaired at the time of diagnosis. This particular child has both inspiratory and expiratory stridor, which have been present since birth. In addition, the bronchoscopy shows severe tracheal stenosis. We have recommended operative repair in all patients through a median sternotomy approach with extracorporeal circulation and reimplantation of the left pulmonary artery anterior to the trachea. The early results of this series (12 patients) were reported in 1992.2 Our experience with pulmonary artery sling surgery now includes 22 patients. There have been no operative deaths in this series. There were 2 late deaths, both in patients with associated complete tracheal rings and complex tracheal reconstruction. The other patients have all had a complete resolution of their symptoms. My recommendation in a child with a pulmonary artery sling in all cases would be repair at the time of diagnosis.
In summary, it is my feeling that pulmonary artery angiography and tracheobronchography are rarely, if ever, indicated in patients with pulmonary artery sling. These patients should be evaluated with echocardiography and bronchoscopy. In addition, it is my strong feeling that all patients with symptoms and a pulmonary artery sling should have such malformations repaired at the time of diagnosis and should not be cared for with medical management.
- Copyright © 1998 by American Heart Association
We appreciate the comments of Dr Backer about the feasibility of 2-dimensional echocardiography in the diagnostic workup of patients with pulmonary artery sling. We believe, however, that pulmonary angiography is still a helpful tool in establishing the correct diagnosis, since echocardiography alone may not always be 100% predictive even in experienced centers.R1 Pulmonary artery sling is such a rare entity that each center should keep and follow the procedures it feels most comfortable with. In patients with pulmonary artery sling diagnosed or suspected by echocardiography, we proceed with combined angiography and tracheobronchoscopy as well as tracheobronchography. In our experience, pulmonary artery sling could be diagnosed by angiography in all 12 patients evaluated during the last 20 years. Preoperative simultaneous examination of the tracheobronchial anatomy by tracheobronchoscopy and tracheobronchography is essential for planning the optimal surgical procedure for each individual patient.R2 R3
We believe that surgical treatment is not always necessary in patients with pulmonary artery sling. Indication for surgical intervention should be made on an individual basis according to the severity of symptoms and results of lung function studies. Some children with pulmonary artery sling may have normal physical capacity and development with only minor respiratory problems without surgery, as demonstrated in our patient.